to mean business 说真的（非正式）

英文释义

To be serious; to be committed to fulfilling a threat, promise, or plan; to be unwilling to be stopped by anything.

例句

My sister is a hard-working and sometimes ruthless executive, and when she says she wants to accomplish something, she means business.

我妹妹是位工作努力，有时很玩命的高管，当她说要做到什么事，她是认真的。